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Getting started and hooked!!

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  • Getting started and hooked!!

    Hello from Hochstadt Germany. I'm ex-military and been living in a little town outside of Frankfurt for over 30 years. 4 weeks ago I was hooking up an irrigation(rainbird drip) system in my yard and had about 50' of 1/2" tubing left over. I'm looking over at my kids swimming in our 1000 gallon Intex pool and thinking " If I lay this on the roof and pump water thru it, what would happen"? Well, the last couple of weeks have yielded a bunch of data and positive results to the point where I'm hooked on solar pool heating and it's about all I think about every day. Lol
    This is where I am now..... I have a 66 square meter( 710 square feet ) flat south facing roof that gets full sunshine from 9:30am till 8:30pm. I loosely coiled 110 meters(360 feet) of 1/2" irrigation tubing directly on the roof and ran it 5.5 meters (18 feet ) down to the pool. The Intex pools tiny cartridge filter was never an option for pumping so the first experiment was with the regular hose faucet. I have a Fluke 52 k/J probe thermometer that is highly accurate and all my measurements were takin using it. The faucet water temperature going into the tubing was 16.1C ( 60.98 F ). Using a Gardena digital flow meter and a ball valve I played with the flow and temperature output till I had a steady 27.4 C ( 81.32F ) at 6 Lpm( 1.58 GPM). I was so impressed with the temperature and just could not believe the increase. I let the system run for over 30 minutes to make sure the tubing had time to cool down but I was amazed that it stayed steady varying only .1 or .2 C up or down. I was absolutely amazed and started thinking about the possibilities of using more tubing 1000, 2000, 3000 feet or more to really jack up the temperature. Up till this point I had done no research on the subject and had no idea that thousands of people make home made systems using irrigation tubing. My first issue was how to pump the water from my pool to the roof 18' above. I bought a submersible sump pump and made the connection to the tubing using a quick connect coupling and I started pumping water from the pool thru the system. The pool water was 23.7 C ( 74.66F) and my output was 31.3C ( 88.34F) at 5 Lpm. This is the point that I got really hooked. I started researching and watching every YouTube video I could find about DIY systems. Series or parallel, series Parallel, tubing sizes and lengths. I've spent days reading everything I could find and think that a 6 coil 500' per coil parallel system would be easy and cheap to build. I will lay the coils directly on my roof just like my test coil ( no boxes or any kind of construction). My reasoning for this very simple system was this. It's a very small pool, an Intex 10' diameter, only 1000 gallons ( 3785 L ). In a 6 coil parallel system with each coil returning 5 LPM @ approximately 30 C that would be about 30 LPM or 1800 Lph. It basically works out to a little more than 2 hours to run the complete volume of the pool thru the system. I know there is other calculations that could be made like outside temperature, wind, heat loss due to evaporation ect. But without getting into the nitty gritty ( I suck at math ) I figure I could always add a coil or 2 or three if needed. I have enough room on my roof for about 12 500' coils if I really wanted to get crazy. The last few days I've played with different flow rates resulting in different temperatures and somehow feel that 5 Lpm at 31 to 32 C is where I want to be. I know from my research that it's better to pump more volume at a lower temperature and I understand that. That's why I think going with a parallel system is key. I've hit a roadblock now. I spent days researching what kind of pump I need to purchase in order to do what I want. I will run 1.5" PVC up(18' up) to the roof and using 1.5" build a supply and return header. I was thinking of installing a 1.5" 3 way ball valve on the inlet hose of my tiny Intex filter. When I want to run the heating system I could simply shut off the filter, turn the valve, and the inlet to the pump would now be open to do its thing. I understand that I would need another valve and T hooked up to the output of the pump as a return to the pool and this valve would be used to adjust the flow rate to the coils. If I thought that I would ever put up a larger pool then I would just buy a sand filter/pump system and run my coils off of that like so many people do but the small pool is all my children need and they are happy with it. So, I think I'm stuck with building a hybrid system using just a pump to navigate around my Intex pump. I hope someone could look over what I plan on doing and give some suggestions and hopefully someone can point me in the right direction when it comes to a pump that can accomplish the lift and volume I need. Thanks for taking the time to read this. John